(Invited) Magneto-Ionic Control of Heterostructures and Interfaces

Abstract

Magneto-ionics has shown promise for energy-efficient nanoelectronics, where ionic migration can be used to achieve atomic scale control of interfaces in magnetic nanostructures, and in turn modulate a wide variety of functionalities. Recently, we have discovered that chemisorbed oxygen and hydrogen on the surface of ferromagnetic films can induce significant Dzyaloshinskii–Moriya interaction (DMI) [1], a handle to introduce topology into nanoscale magnets. This has enabled direct tailoring of skyrmions winding number as well as wall type at room temperature via oxygen chemisorption. We have also demonstrated a sensitive and reversible chirality switching of magnetic domain walls [2] and writing/deleting of skyrmions [3] via hydrogen chemisorption/desorption. These chemisorption induced magnetic effects on controlled ferromagnet surfaces offer an ideal platform to gain quantitative understanding of magneto-ionics at buried interfaces, where the ionic motion can be further controlled by an electric field [4]. These effects are relevant for 3-dimensional information storage as a potentially contactless way to address spin textures, such as in interconnected nanowire networks [5]. Interestingly, nanoporous metal foams made of random assemblies of nanowires have found applications in deep-submicron particulate filtration, relevant to combatting COVID-19 and air pollution. Such foams are efficient, breathable, light-weight, robust, and can be reused and recycled [6]. Our mask design based on such foams has been selected by BARDA-NIOSH as a Phase 1 Winner of the Mask Innovation Challenge [7].[1] Science Advances, 6, eaba4924 (2020).[2] Physical Review X, 11, 021015 (2021).[3] DOI: https://doi.org/10.21203/rs.3.rs-575830/v1[4] ACS Applied Materials and Interfaces, 13, 38916−38922 (2021).[5] Nano Letters, 21, 716-722 (2021).[6] Nano Letters, 21, 2968-2974 (2021).[7] https://drive.hhs.gov/mask_challenge.html.This work has been supported by the NSF (DMR-1905468, DMR-2005108, ECCS-1933527), the nCORE SMART center through SRC/NIST, the University of California and Georgetown University.